Discrimination of O. viverrini, C. sinensis, H. pumilio and H. taichui using nuclear DNA-based PCR targeting ribosomal DNA ITS regions.
Small liver and minute intestinal flukes are highly prevalent in Southeast Asia, and in mixed infections, their eggs are difficult to differentiate morphologically in fecal samples. PCR assays targeting the ITS regions in ribosomal DNA were designed to identify and differentiate species. The PCR amplicons of Opisthorchis viverrini, Clonorchis sinensis, Haplorchis pumilio, and Haplorchis taichui were 800, 820, 1250, and 930 bp for the ITS1 region, and 380, 390, 380, and 530 bp for ITS2, respectively. The ITS1-region amplicon sizes successfully differentiated 4 species, while only H. taichui were significantly different from the other 3 species in the ITS2 region. PCR assays were employed for preliminary analysis using fecal samples diagnosed as having "small trematode eggs" by modified thick smear, showing 76.2% sensitivity for ITS1 and 95.2% for ITS2.
Sato
Megumi
M
Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand.
Thaenkham
Urusa
U
Dekumyoy
Paron
P
Waikagul
Jitra
J
D000818:Animals; D003004:Clonorchis sinensis / Q000145:classification / Q000235:genetics*; D018509:DNA, Helminth / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics*; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D006578:Heterophyidae / Q000145:classification / Q000235:genetics*; D009891:Opisthorchis / Q000145:classification / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*; D013045:Species Specificity
D018509:DNA, Helminth; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer